plumiWhat are electrolytes and what happens during electrolysis?: OCR GCSE Chemistry B questions
Every OCR GCSE Chemistry B exam question on C3.3 What are electrolytes and what happens during electrolysis?, 2018–2025, with its mark scheme and examiner’s report.
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Q9(a)
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Q9(b)(i)
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The whole paper ↗Q2(a)
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Q2(b)(i)
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The whole paper ↗Q5(a)(i)
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Q5(a)(ii)
The whole paper ↗Q5(a)(iii)
The whole paper ↗Q5(a)(iv)
The whole paper ↗Q5(b)(i)
The whole paper ↗Q5(b)(ii)
The whole paper ↗Q5(b)(iii)
The whole paper ↗Q4(b)(i)
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Q4(b)(ii)
The whole paper ↗Q4(c)(i)
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All 57 questions on What are electrolytes and what happens during electrolysis?, as a list
- June 2025, Paper 2 Foundation, Q9(a) (2 marks): Oxygen gas forms at the positive electrode. Which two statements give correct reasons why oxygen forms at the positive electrode? Tick (✓) two boxes. Copper rea
- June 2025, Paper 2 Foundation, Q9(b)(i) (1 mark): Suggest one change to the apparatus so that the volume of oxygen gas can be measured. [1]
- June 2025, Paper 2 Foundation, Q9(b)(ii) (2 marks): Describe how the student uses the new apparatus and a stop watch to find the rate that oxygen gas forms. Include in your answer: • what results they need to col
- June 2025, Paper 2 Foundation, Q9(c) (3 marks): The student measures the mass of the electrodes before and after the electrolysis. The table shows their results. Negative electrode Positive electrode Mass bef
- June 2025, Paper 3 Higher, Q3(b)(ii) (1 mark): Which half equation shows the oxidation of zinc? Tick (✓) one box. Zn2+ + 2e– Zn Zn2+ + e– Zn Zn2+ + e– Zn Zn2+ + 2e– Zn [1]
- June 2025, Paper 4 Higher, Q2(a) (2 marks): Oxygen gas forms at the positive electrode. Which two statements give correct reasons why oxygen forms at the positive electrode? Tick (✓) two boxes. Copper rea
- June 2025, Paper 4 Higher, Q2(b)(i) (1 mark): Suggest one change to the apparatus so that the volume of oxygen gas can be measured. [1]
- June 2025, Paper 4 Higher, Q2(b)(ii) (2 marks): Describe how the student uses the new apparatus and a stop watch to find the rate that oxygen gas forms. Include in your answer: • what results they need to col
- June 2025, Paper 4 Higher, Q2(c) (3 marks): The student measures the mass of the electrodes before and after the electrolysis. The table shows their results. Negative electrode Positive electrode Mass bef
- June 2024, Paper 3 Higher, Q5(a)(i) (2 marks): anode. [2]
- June 2024, Paper 3 Higher, Q5(a)(ii) (1 mark): Why is the formation of copper from copper ions a reduction reaction? [1]
- June 2024, Paper 3 Higher, Q5(a)(iii) (2 marks): Explain why copper and not hydrogen is formed at the cathode. [2]
- June 2024, Paper 3 Higher, Q5(a)(iv) (1 mark): Describe one observation that can be seen as the electrolysis proceeds. [1]
- June 2024, Paper 3 Higher, Q5(b)(i) (2 marks): Complete the balanced symbol equation for the electrolysis of aluminium oxide. Al 2O3 Al + O2 [2]
- June 2024, Paper 3 Higher, Q5(b)(ii) (2 marks): Which two statements explain why the industrial electrolysis of aluminium oxide is very expensive? Tick (✓) two boxes. A high temperature is needed for the proc
- June 2024, Paper 3 Higher, Q5(b)(iii) (2 marks): Describe a test to identify oxygen. [2]
- June 2023, Paper 1 Foundation, Q4(b)(i) (2 marks): Which two statements about the electrolysis of aluminium oxide are correct? Tick (3) two boxes. Al 3+ ions move to the positive electrode. Oxygen is also formed
- June 2023, Paper 1 Foundation, Q4(b)(ii) (2 marks): Complete the sentence to explain how the aluminium is formed. Use words from the list. atoms ions gain lose molecules share Al 3+ ions electrons to form alumini
- June 2023, Paper 1 Foundation, Q4(c)(i) (1 mark): Why does the process of making aluminium by the electrolysis of molten aluminium oxide use a lot of energy? [1]
- June 2023, Paper 1 Foundation, Q4(c)(ii) (2 marks): A student states that aluminium can be extracted by the electrolysis of aluminium sulfate solution. Explain why the student is wrong. Use the reactivity series:
- June 2023, Paper 3 Higher, Q6(a) (1 mark): Why is the aluminium oxide molten? [1]
- June 2023, Paper 3 Higher, Q6(b)(i) (1 mark): Explain why the reaction is described as oxidation. [1]
- June 2023, Paper 3 Higher, Q6(b)(ii) (1 mark): Name the species which is oxidised in the equation. [1]
- June 2023, Paper 3 Higher, Q6(b)(iii) (1 mark): Explain why carbon dioxide is also produced at the anode. [1]
- June 2023, Paper 3 Higher, Q6(c) (2 marks): Write the balanced half equation for the production of aluminium at the cathode. [2]
- June 2023, Paper 3 Higher, Q6(e) (2 marks): A solution of aluminium sulfate contains aluminium ions. Amit says it should give aluminium at the cathode when it is electrolysed. Explain why Amit is wrong. [
- June 2022, Paper 1 Foundation, Q9(a) (2 marks): When molten compounds are electrolysed: • the metal is made at the negative electrode • the non-metal is made at the positive electrode. State what is made at e
- June 2022, Paper 1 Foundation, Q9(b)(i) (1 mark): Draw a line to connect the box labelled electrode with the correct part of the diagram. [1]
- June 2022, Paper 1 Foundation, Q9(b)(ii) (2 marks): Explain why Nina places a measuring cylinder containing sodium chloride solution over each electrode. [2]
- June 2022, Paper 1 Foundation, Q9(b)(iii) (1 mark): Sodium is not made at the negative electrode when sodium chloride solution is electrolysed. Name the gas made at the negative electrode. [1]
- June 2022, Paper 2 Foundation, Q3(b) (1 mark): The fuel cell is filled with potassium hydroxide solution rather than pure water. This is because potassium hydroxide solution is a better electrical conductor
- June 2022, Paper 3 Higher, Q11(a)(i) (1 mark): At which electrode is aluminium formed? [1]
- June 2022, Paper 3 Higher, Q11(a)(ii) (1 mark): Give one reason for your answer to (a)(i). [1]
- June 2022, Paper 3 Higher, Q11(b)(i) (1 mark): Explain why hydrogen, not sodium, is made at the negative electrode when sodium chloride solution is electrolysed. [1]
- June 2022, Paper 3 Higher, Q11(b)(ii) (2 marks): Write the half equation for the formation of hydrogen at the negative electrode. [2]
- June 2022, Paper 3 Higher, Q11(c) (2 marks): Kareem electrolyses sodium chloride solution. Hydrogen gas and chlorine gas are made. Describe what Kareem needs to do to measure the volumes of hydrogen gas an
- June 2022, Paper 4 Higher, Q5(c)(iii) (1 mark): The reaction of copper in Stage 2 can be represented by a half equation: Cu2+ + 2e– Cu Is copper oxidised or reduced in this half equation? Explain your answer.
- November 2021, Paper 2 Foundation, Q3(a) (2 marks): Explain why molten aluminium oxide conducts electricity but solid aluminium oxide does not. [2]
- November 2021, Paper 2 Foundation, Q3(b)(i) (2 marks): Give the name of the product formed at each electrode in Fig. 3.1. Product at positive electrode Product at negative electrode [2]
- November 2021, Paper 4 Higher, Q8(a)(i) (2 marks): Before electrolysis, solid aluminium oxide is dissolved in a hot, molten compound called cryolite. The formula for cryolite is Na3Al F6. Explain why the formula
- November 2021, Paper 4 Higher, Q8(a)(ii) (2 marks): The hot cryolite dissolves the aluminium oxide to form a molten solution. Explain why solid aluminium oxide has to be made into a molten solution before electro
- November 2021, Paper 4 Higher, Q8(b)(i) (4 marks): Describe what happens at each electrode during the electrolysis. [4]
- November 2021, Paper 4 Higher, Q8(b)(ii) (1 mark): The melting point of aluminium metal is 660 °C. What temperature should the inside of the tank be to make sure that aluminium leaves the tank as a liquid? Put a
- November 2020, Paper 1 Foundation, Q5(b) (2 marks): Lithium is made by the electrolysis of molten lithium chloride. Which substance is formed at each electrode? Put a ring around each correct answer. Anode (posit
- November 2020, Paper 2 Foundation, Q10(a)(i) (3 marks): Complete the table by predicting the products formed at each electrode when electricity is passed through concentrated copper chloride and dilute sodium sulfate
- November 2020, Paper 2 Foundation, Q10(a)(iii) (2 marks): Explain why, at the negative electrode: • copper metal is formed when electricity is passed through dilute copper chloride, but • hydrogen gas is formed when el
- November 2020, Paper 2 Foundation, Q10(b) (2 marks): This is a list of apparatus Sundip uses to pass electricity through the solution of dilute sodium chloride: • electrodes • leads and clips • a battery • a beake
- November 2020, Paper 3 Higher, Q10(c) (2 marks): Lithium is made by the electrolysis of molten lithium chloride. Name the product formed at each electrode. Cathode Anode [2]
- November 2020, Paper 4 Higher, Q2(a)(i) (3 marks): Complete the table by predicting the products formed at each electrode when electricity is passed through concentrated copper chloride and dilute sodium sulfate
- November 2020, Paper 4 Higher, Q2(a)(ii) (2 marks): Sundip uses tests to identify the gases formed in her experiments. Draw lines to connect each gas to its correct test and result. Gas Test and result relights a
- November 2020, Paper 4 Higher, Q2(a)(iii) (2 marks): Explain why, at the negative electrode: • copper metal is formed when electricity is passed through dilute copper chloride, but • hydrogen gas is formed when el
- November 2020, Paper 4 Higher, Q2(b) (2 marks): This is a list of apparatus Sundip uses to pass electricity through the solution of dilute sodium chloride: • electrodes • leads and clips • a battery • a beake
- June 2018, Paper 1 Foundation, Q6(a) (3 marks): The electrolysis produces chlorine. Complete the sentence by putting a ring around one word in each pair. The chlorine / chloride ions are attracted to the posi
- June 2018, Paper 1 Foundation, Q6(b) (3 marks): Nina electrolyses a solution of sodium chloride. She uses this apparatus. sodium chloride solution Nina thinks that the experiment makes chlorine gas at one ele
- June 2018, Paper 3 Higher, Q10(a) (1 mark): Which statements about the electrolysis of water are correct? Ticks (3) two boxes. The equation for the formation of hydrogen gas is 2H+ + 2e– H. Hydrogen is pr
- June 2018, Paper 3 Higher, Q11(a) (2 marks): The ions present in molten aluminium oxide are Al 3+ and O2–. Write half-equations for the formation of aluminium and oxygen in the electrolysis cell. Formation
- June 2018, Paper 3 Higher, Q11(b) (3 marks): Aluminium oxide does not conduct electricity when it is solid. It conducts electricity when it is molten. Explain why. [3]
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